Yes, FWIW, I've generally had better success monitoring "stat", "srvr" or "mntr". Any of these can tell you the server's leader/follower state, and the latter offers a rich set of usage metrics. There are more details in the documentation here:
https://zookeeper.apache.org/doc/r3.4.9/zookeeperAdmin.html#sc_zkCommands Chris Nauroth On Wed, Nov 30, 2016 at 10:52 AM, Michael Han <[email protected]> wrote: > 'ruok' is the very basic sanity check of the ZooKeeper server process - it > will return ok as long as the server process is up and reachable through > network (in fact, the server does not nothing but immediately return ok > upon receives 'ruok' request). > 'ruup' does seem a better naming semantically to me. > > On Tue, Nov 29, 2016 at 5:10 PM, Ben Sherman <[email protected]> wrote: > > > I expect if none of the 4 letter commands except ruok give a response, > then > > the server is definitively not okay. ruup vs ruok maybe? We see the > server > > popping into a looking state quite often, and it's the cause of 100% of > our > > outages involving zookeeper. This isn't an initial state, it's down > until > > a restart. > > > > On Tue, Nov 29, 2016 at 3:08 PM, Flavio Junqueira <[email protected]> > wrote: > > > > > It looks like the server is in the LOOKING state, so it is not serving > > > request but it is up. I'd say that ruok should return imok as long as > the > > > server is up, it's not necessarily a health check. We could review the > > > semantics of the commands if this behavior and others are confusing. > > > > > > -Flavio > > > > > > > > > > On 29 Nov 2016, at 19:54, Ben Sherman <[email protected]> wrote: > > > > > > > > Four letter word ruok is returning imok when the server is decidedly > > not > > > > okay - is this the expected behavior? > > > > > > > > bsherman@zk1:~$ nc localhost 2181 <<< mntr > > > > This ZooKeeper instance is not currently serving requests > > > > bsherman@zk1:~$ nc localhost 2181 <<< ruok > > > > imok > > > > > > > > I'm running 3.4.9. > > > > > > > > --ben > > > > > > > > > > > > -- > Cheers > Michael. >
